Bicycle Frame Clearance Calculator
Check that a tire fits in your frame. Use the calculator below. Results update as you type.
How the Bicycle Frame Clearance Calculator Works
This calculator works by adding a safety margin on each side of the tire and comparing the total with the measured frame gap. It covers the fork crown, seat stays and chainstays.
- Measure the tightest frame gap, for example 44 mm.
- Enter the tire's real width, for example 32 mm.
- Choose a margin per side, for example 6 mm.
- Read the result: 32 + 12 = 44 mm, so the tire just fits.
The Formula
The formula is Required Gap = Tire Width + 2 × Margin per Side.
Required Gap = W_tire + 2 × Margin Pass = Measured Gap ≥ Required GapWorked example: a 40 mm tire with a 4 mm margin needs 48 mm. With a 6 mm margin it needs 52 mm (2.05 in).
Mud, wheel flex and tire growth on wide rims all eat into the margin.
Conversion Table
The conversion table gives the minimum frame gap for 10 tire widths with 4 mm and 6 mm margins per side. Widths run from 23 mm to 57 mm (2.24 in).
Use the 6 mm column for gravel and muddy riding. Use the 4 mm column for dry road riding.
| Tire Width (mm) | Tire Width (in) | Gap with 4 mm per Side | Gap with 6 mm per Side | 6 mm Gap (in) |
|---|---|---|---|---|
| 23 | 0.91 | 31 | 35 | 1.38 |
| 25 | 0.98 | 33 | 37 | 1.46 |
| 28 | 1.10 | 36 | 40 | 1.57 |
| 30 | 1.18 | 38 | 42 | 1.65 |
| 32 | 1.26 | 40 | 44 | 1.73 |
| 35 | 1.38 | 43 | 47 | 1.85 |
| 40 | 1.57 | 48 | 52 | 2.05 |
| 45 | 1.77 | 53 | 57 | 2.24 |
| 50 | 1.97 | 58 | 62 | 2.44 |
| 57 | 2.24 | 65 | 69 | 2.72 |
Measure the real mounted tire width; it often exceeds the label on wide rims.
What Is the Bicycle Frame Clearance Calculator?
The Bicycle Frame Clearance Calculator is a tool that checks whether a tire fits a bicycle frame and fork with room to spare. Frame makers list maximum tire width, but real clearance depends on rim width and tire model.
A tire that touches the frame wears through paint and carbon. The calculator puts a number on the margin.
Common Uses
This calculator has 4 uses: wider-tire upgrades, gravel conversions, mudguard planning and frame shopping.
- Upgrade to wider tires: Find the widest safe tire.
- Convert to gravel: Check knobby tire clearance.
- Plan mudguards: Add fender thickness to the margin.
- Shop for frames: Compare listed and measured clearance.